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IR1176
Fig. 4 PLL loop filter component definitions
4 - PLL Damping factor calculations:
P = ππE-3 x Rf (KOhms) x C(nF) x fn(KHz)
Typical value for P is 0.707. (Critically damped)
5 - Advance timing:
Tadv(nsec) = RADV (KOhms)*10 - 10
Where RADV is resistance from RADV1 or RADV2 to ground.
Example C: RADV=10Kohms will result in Tadv=10*10 - 10 =90 nsec .
6- Dead time calculations:
Td(nsec)=0.69*Rdt(KOhms)*Cdt(pF) + 5 (For Vdd=5 V)
Where Rdt is resistance between pins DTIN1 and DTOUT1 or DTIN2 and
DTOUT2. Cdt is capacitance from DTIN1 or DTIN2 to ground.
3 - PLL Natural frequency:
ωωn =2ππfn(KHz)=
√√
Ichpump(uA) x Kvco_ac(KHz/V) / C(nF)
Choose Cf such that
+ 6=106 nsec.
Example D: Rd=2KW and Cdt=100pF will result in Td=148.35nsec.
+ 6
Td(nsec)=0.69*Cdt(pF)*(Rdt(KΩ)+0.15) (For Vdd=5V)
